Antigens typically include bacteria, viruses, and other organisms or materials that can invoke an immune response. Antigens often pose a potential risk to human health, such as when the antigens are present in food, water, and air supplies. Therefore, the detection and quantification of such antigens is often an important or necessary function in various situations.
Current methods of detecting antigens are often time-consuming or costly. For example, for microorganism contaminations, cell culture and biochemical methodologies may take days to weeks before results are obtained. Methods such as solid phase cytometry (SPC), polymerase chain reaction (PCR), surface plasmon resonance (SPR), and similar techniques detect antigens based on surface proteins or nucleotide detection. While such methods may detect antigens in minutes to hours, these methods are costly, require manual work, or have limited detection capabilities.
Another significant drawback to all of the above methods is that they are typically difficult to implement in an on-line manner. These methods usually require that an antigen of interest first be concentrated using membrane filtration or other devices. A condensate then often needs to be collected from the filter, or the antigen of interest needs to be labeled on the membrane prior to the measurement.